CA1337292C

CA1337292C - Method of and compositions for reducing wear on surfaces subjected to frictional forces

Info

Publication number: CA1337292C
Application number: CA000599824A
Authority: CA
Inventors: Josef Fodor; Jack Schofield
Original assignee: British Technology Group Ltd
Current assignee: BTG International Ltd
Priority date: 1988-05-18
Filing date: 1989-05-16
Publication date: 1995-10-10
Anticipated expiration: 2012-10-10
Also published as: AU3697789A; NO904941D0; NO302300B1; IE891588L; HU209491B; HUT56389A; NZ229188A; HU893619D0; IE61949B1; AU622912B2; ES2017252A6; GB8811696D0; DK274090A; WO1989011518A3; EP0420868A1; DE68909236T2; WO1989011518A2; EP0420868B1; DK274090D0; NO904941L

Abstract

A method and composition for reducing wear on surfaces subjected to frictional forces. The lubricating compositions can be applied in a carrier which may be organic or inorganic in nature. They function by providing a regime in which multimolecular layers are adsorbed onto the surfaces to be protected, thus enabling comparatively thick protective films to be built up on the surfaces subjected to fractional wear.
The molecules having the property are essentially single or condensed unsaturated ring systems which comprise at least one six-membered unsaturated heterocyclic ring comprising at least one heterocyclic moiety which acts as a hydrogen acceptor and a hydrogen donor moiety. If substituents are present they should not create steric hindrance and/or render the molecule so basic or acidic as to alter the steric geometry of the molecule as to prevent the interaction of the active groups.

Description

DESCI~PT~ON
"METHOD OF AN~ CO~IPOSITIONS ~OR ~EDUC ING WEAR ON
SURFACES SUBJE~TED TO FRICTIONAL ~ORCES"
The present invention relate~ to a method of, and ~o~po6ieions for, redu~ing wear on s~rface~ ~ub~ected to f~iction~l forces, p~r~ieulsrly ~etween mo~ng surfaces.
The prim~ry purpo~e of lubrieation is separat~on of moving surfRces to mln~m1se friction and wear.
Se~eral dist~nct regime~ are commonly reco~nised in the field of lubr~ca~ion, Thus in fluid film lubrication the load is ~upported entlrely by pressures within the separ~e~ng fluid f~lm. This film preCsure is frequen~ly gener~ted by relat~ve motion of ~e ~urfaces involved J which pumps the lubricant lnto a con~ergln~. wedge-shaped ~one. The hydro dynamic beha~iour of such bearings i8 completely dependene on ~e viscou~ behaviour of the lubricant. Bo~h the load-~upporting o$1 fllm pres~ure and the power 1088 ~re fun~tions of lubric~nt v1sco~ity ln combination with the geometry and she~r r~te imposed by the bear~ng opersting eonditlon~.
A~ the ~evé~ity of opera~lng condltlons lncrea~es, a po~nt $~ e~entu~lly reached where the load c~n no longer be c~rried completely by o~l-film ~upport.
High spots, or a~per~tles of the matinB ~urf~ces must t~ en shear with the lubtic~nt in lo~d ~upport ~nd the l~br~caeion reglme shifts from full-film eo mixed-fil~
and then to complete boundary high load, low speed, low viscosity lubricant, misalignment, higll surface roughness or ~n in~dequate supply of l~bri~nt. ~7ith bound~ry lubricntion, chen~ical add~ eives in th~
lubricating composi~ion and chemical met~llurg~ c~l, ~nd mechanic~1 f~ctors in~olvin~ the two rubbing surfaces will deter~lne the extent of we~r ~nd the degree of frictlon.
Under boundary cond~tlons of lubrieation, met~l contact through the oil film result~ in ~unctions of asperi ties ~nd subsequent lae~al tearing on microscopic scale. As loads incre~se these conta~ts become more frequent and result in more pl~sti~
de formAtion, h~gher ~emper~eures and welding with ~elzure eventually o~currine on a ~ross and de~st~tlng sc~le, Hypoid gear~, since ~hey ~mpose severe sllding condition~ in comblnAtlon with high contact seress ~re pArt~culArly ~u8ceptible to thls ~ype of damage. The org~nic lubri~arlt fllm normelly present becomes ineff~ctive under the ~ ntense heat whlch le~ds to very h~Bh surface temperatures.
To combat welding under such extreme condieions~
ex~relae pres~ure lubricants were de~eloped. Sllch lubricAnts contflin ~dditi~e~ which re~ct at the hlgh contact te~perature~ to form high-meltlng ino~nic lubricant fllms on the met~1 ~urface~ which prevent massive welding And bre~k~own. Generally, these additives consist of sulphur, c~lorine, pho~phoru~ ~nd lead co~pounds which act eit~er by providing l~yer~ of low shear strength to m~nimi~e metal ee~rin~ or by servin~ as fluxing agen~s ~o con~amin~te the metal surface snd prevent welding. Since ~11 extreme-pressure additiveg are affected by chemlcal ~ction, l.e. the ormation of covalent bonds, their use i~
generally avoided to elimina~e posælble eorrosion difficul~ie~ .
Dry sliding, which involves solid-to-solid contactl not infrequently exists, e~en when adequ~te flul~ fil~ lubricat~on is provided. ~ry sliding can occur for example, in st~rtin8 up of a machlne~ with ~isal~gn~ent or ~n~dequate clearance dur~ng run-in, during reversal o~ direction, ~nd during any de~ay~ or interruptions in ~upply of t~e lubric~ting fluid.
Where conventional oils snd gre~e~ cannot be used becAuse of extreme temperature~l hig~ vaeuum, radi~t~on, or e~ntaminatlon, ~h~n coatlngR of dry lubrlcant6 ha~e been appl~ed to reduce the ~igher fri~tion and more extens~ve we~r which otherwise obtaln on rubbln~ ehe structurRl mAterl~ls ~g~inst each oeher.

Thu~ the gofll of lubrlcation 1~ eli~ination of this wear and minim~sing of fri~ion wh~¢h would other~ise be encounte~ed in dry sl~ding. Whil~t th~s c~n be ~ccomplished by complete sepsration of the rubbing surf~ce6 fl8 ~y a full film of fluid lubrie~ntJ
gener~lly ~uch compleee separAtion i~ not possible under all working cond~tions ~nd 88 a re~ult, ~urface ~hemical effects h~ve been ~roug~t lnto play in boundary lubrication to reduce fr$ctLon and we~r which doe& occur in bound~ry lubricflt~on. Thus anti-wear a8ent~ have been ~dded to liquid lubtic~nts wh~ch produce a surf~ce film on the sl~ding p~rts by eiehe~
a chemi~al or physlcAl adsorption mechanism, the film redu~in~ friction and wear under boundary lubrication conditions .
A wide variety of compounds have been used fo~
impro~ing lubrication under boundsry film ~onditions.
Thus compound~ containing oxygen such BS fa~ty acids, esters snd ketones~ co~pou~ds cont~ining ~ulphur or co~bin~tions of oxygen ~nd sulphur, organ~c chlor~ne compounds suc~ as chlorinated ~xes~ organic ~ulphu~
compount~ ~uoh ~ ~ulphurlsed fa~ and ~lphurised olefine~ compounds containlng bo~h chlorine and sulphu~, org~nic pho~phorou~ compounds such ~s tricregyl pho6phate, th~opho~ph~tes and phosph~tes ~nd ~1BO org~n~c le~d compounds h~ve been u~ed, When t~e cond~ tions in bound~ry lubric~t~on are mild, polar additlves h~v~ng fl pol~r group ~t one end o~ the mole~ule ~Q~ A ~olubll~sing group ~t the other - usu~lly a long chsin ~ydroc~rbon ~o effect solubili~ation in the lubricsting o~l, hAve been used to provide ~n ~dherent ~d~orped film over metall~c ~urf~ce~. A clas~ of heterocycllc co~pounds usefu~ B8 additi~res ~rhich provide ~riction modifie~tion ~nd ilnproved fuel economy are d~selosed in WO 87/0596 ~nd h~ve the gener~l formula:

(~~Y
~C~X)e A A A
Il 1i 11 wherein Z iB S, NR, N-C~ , NC~ , N-C-R, PR or PRA, where~ n A i~ O or S And R is H, Al~cyl, alkenyl, hydrocarbyl ~cyl, hydrocarbyl phenolate or - (CH~)mQ, w~ere m i~ 1 to ~bout 12, and Q is O-alkyl or N-Alkyl, X ls independent ly H, ~OOH, NH2 ~ CONH2, NHNH2 OR
COR, NHR, OH, S~, or CN wherein R i~ the 8~me R8 defined ~bove; p i8 0 ~o 7; e i8 0 t:o 2 wherein e+p i8 2 to abou~ 4; T is NH2~ M~R wherei~ R is the sAme a~
deflned ~bove, SH, 0~ or their t~utomers~ hydrocarbyl A
acyl or hyd~ocarbyl phenolflte; ~nd Y i8 ~N, ~NH2~ C02H

or CH2NH2 wherein A is the 8~me as defined ~bove.
Such ~dsorped fllms of ~dditive h~ve h~therto only been ~ucces~ful under rel~ti~ely mild bound~ry lubricatlon cond~tions, primar~ly becau~e the thicknes~ of ~uch filmOE i8 very low ~nd usually of the order of one nanometer. Vnder more severe cond~tions of boundary lubriç~tion, sub6tances llke ~r~cre8yl phosphAte or zinc dislkyl dithiophosphates hAve been foun~ nece6sary and in ex~eme rubbing conditions where severe metal-to-met~l contact would ot~erwise be encoun~ered~ ~ctive sulphur, chlorine and lead compounds h~ve been found essen~iAl. Such ~dditives ho~ever react chemically to form low shear 6trength surface layers suc~ as lead sulph~de ~on ~hloride or ion sulphide. ?h~Y sllrf~ce l~ye~ then prevent5 destruc~ive welding, exce~ive metal tr~nsfer and severe surface breakdown, Such che~ical reactivi~y ~ith the ~urfAces of t~e sliding p-rtY however ig not in general desirable ant iR only undertaken when no other alternati~e iR av~lable.
A~ indicated, the pol~r type of compound which forms an adherent ~d~orped f~lm o~er the mo~ng surfaces i8 much to be preferred, but the thicknesses of ~uch fil~8 w~ich ~ve been possible by the u~e of hitherto known ~ddit~e~ ln lubrica~ng compo~tions h~ve produced in~ufficient thickne8se8 of fldsorped 1 3372q2 f~lm to funct~on under ~ny eond~tion~ ot~er tha~ mild condition&.
~ t is an ob~ece of the present in~ention to provlde a lubri¢ating regime whereby adherent ~dsorbed f~lms of pOlflr mAteri~l ~re provided l~p to 1,000 times thicker than ha~e hi~her~o been poss~ble.
The present ln~ention ~oncerns a ratic~1 ad~ance ~n lubrication by pro~iding A regime ln which ~ultimolecul~r layers ~re adsorbe~ onto the surf~ces to be protected thUfi enAbling co~parAtlvely thick pro~ective film~ to be built up on suface~ sub~ec~ to fr~ctional ~e~r. Ie has now been found that certain molecules hAve ~he property of forT~$rlg such mult~molecular l~yers w~en con~acted with the surface as by incorporation In a carrier which i~ eontinuou~ly or intermi~tently brought into cont~ce with ~t lea~ a portion of the ~urface to be protected. The ~olecules ~-~ich ha~e been found to ~ve t~ s property are e~sentially ~ingle or eondensed unsaturated ring sy6tem~ which co~prl~e ~t le~t one ~ix~membeted unsaturAted he~erocycllc ring co~rising flt leAst one heterocycll~ moiety whi~h flCt8 a4 ~ hydro~en ~cceptor, t~le molecule Al80 compr~sing at les~t one hydrogen donor moiet~, The molecule~ may ~omprise other f~ve or 8 ~x-membered unsatur~ted ring6 w~ich ~ogether with t~e s~id 61x-membered un~turated heterocyclic rin8 form ~ eonden~ed r- ng syBtem.

1 3372q2 ~ he multimolecular layers of the lubricAtlng re~ime of the pre~ent lnven~ion ~re ~uilt up ~y initial ~dsorption of a layer of molecule~ onto the surface to be proeected $ollo~ed by ~d~orption of further molecules onto the initial layers to for~ a second layer and yet further adsorption to form more layers untll films up to about l ~lcrometer thick ~re formed. ~i~hout ~lshing to ~e bound by theo~y it believed tha~ presence of both hydrogen donor and ~ydrogen ~ceep~or mo~etie~ in the heteropolar molecules enable~ thi~ ad~orption to take place.
Whilst unsubstitu~ed heteropol~r m~lecules are prefer~ed sub6tituents ~y be present on the eteropolar molecule~ prov~ded they do not ~lngly or collec~ively prevent interaction of the hydro.e.en donor ~nd acceptor ~oieties as by ~teric hindrance. T~us, for example, hydrocArbon ~ubstituents such as Alkyl ~roup~ should not con~ain mo~e ehan four carbon AtomS
preferably not more than two carbon atoms. W~en the ~ub~tit~ent is ortho to either the heteroato~ or the hyd~oxyl group the ~teric hindr~nce effe¢e ig likely to be ~reate~ than when said ~ubstituent is in the met~ or p~ra po6itlon to either the heteroa~om or 4 hydroxyl gro~p. Alkene and alkyne subst~ent~, carboxy~ cont~ini~g and ~mi~e cont~ning sub~tuents ~ill all effect the ~ctl~ity of ~he he~eropol~r molecules and should be svoided.

g In one embodiment of the invention ~he~efore, a method i~ provided of reduclng wear on a ~urfHce ~hlCh i8 sub~ect to frietionsl forces which compri~es forming and ~aint~ining on said ~urface ~ pro~ective layer composed of ~wo or more ~olecula~ layers of B
heteropol~r compound ¢o~pri~lng at least one uns~turated heterocycllc s~x-membered ring in which at least one hetero~to~ moiety ~cts a~ a hydro~en acceptor and ~n which said compound al80 compri6e~ at lea~t one hydrogen donor moiety, ~aid heteropolar co~pound h~ving no substituent which by itse~f or to~ether with another 6ubstituent or subs~i~uent~
create~ such ste~ic h$ndrance and/or ~ender~ the molecule so b~sic or acid$c or so alter~ the ~teric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor mo~e~ies of ~ne molecule of heteropol~r co~po~nd with the hydrogen donor and ac~eptor moiecles of ~nother molecule of said heteropolar compound.
For~ation of the multimoleculAr layer of heteropol~r molecules mRy be effected by incorporaeing the heteropolar co~pound in e~rrier whlch i~ ~rought into contact ~ith the surface to be lubricated. It has been found that the heteropolar molecules ~lgrate ~hrough the carrier onto ehe ~rface to be lubricated ~nd bu~ld up on th~t surf~ce ~o fo~m multi~ole~ula~

1 3372q2 - l o-layers. The e~rrier m~y be a liquid such as ~n oil or grease or may even be aqueous . Sol $d c~rrlers ~re al~o fe~s~ble Quch as poly~mide pl~tlc~ such ~8 those used eo build up worn machi~ery parts ~uch ~8 d~ive sh~fts and the like. Inco~por~tion of a heteropolar compound in the plastic material en~blec ~
multimoleculAr layer of heteropolar molecules to form not only on the surf~ce of t~e pl~stic by m~gr~tion throug~l the plAstic material b~t also by tr~nsfe~ from the surface of the plastic to ano~er surfAce ~hich rubs ag~inst the surface of t~e plast~c.
It has 81t~ been found ehe.t ~lle heteropol~r molecules m~gr~te laterally o~er the surf~ce on wh~ch ~hey are ad~orbed beyo~d the boundarles of contact of that surface with the ~rrier ~ateri~l. Cont~ct of the c~rrier ~th t~e ~ole of the surface to be pro~ected ~8 not therefore necess~ry $n order to form a lubricating l~yer of heteropol~r molecule~ over al 1 the ~ur~ce to be protected. Nor ~s lt necessary to ha~e continuou~ contac~ between c~rrier ~nd surf~ce to be treated, but intermlttent contact is also effective. The ~ult$mole¢ulsr l~yer is not of course formed in~tant~neously but builds up over ~ per~od of ti~e. Relative mo~ement of cArrler and ~urface ~o be protected aceelerate t~e ~orm~tlon and m~$nt~inanee of the multimoleeul~r layer of hete~opol4r molecules on the 8urface to be prote~ted.

-11 1 3372~2 The heteropolar molecules ~lgrRte t~rough the c~rrier ~o the interf~ces of the c~rrler wit~ the su~roundlng environ~ent. Unsub4tituted heteropolflr heterocyclic un~aturated sin~le or conden~ed ring system~ hRv~ng the afore~ent~oned hydrogen donor and acceptor moiet~e~ ha~e this property of migr~tion.
Any -~ubstituents in such heteropolar molecu~e~ should not exert such a solubilizing effect on the heteropolar molecules that they lose their ~bility to mi~rate thro~h the c~rrier to the ~ neerfaces of the c~rrier'~ en~iron~ene. Since _ m~or ~pplication o~
~he eompounds o~ the in~ention i~ ~n oils and greases it is e~ent~ ~1 ehnt t~e molecule~ ~hould no~ exe~t 8UC~ a solubilizing effect that they f~il to migr~te.
~onsequent~y, where they are ~o be ~dded to oils and gre~ses ~ny substituted groupings should not "over solubilize" the molecule. Therefore hydrocsrbon substituents should not ~ontain ~ore than 4 eQrbon ~toms I preferably not more than 2 carbon ~oms-According to snothe~ embodiment o~ the presentinven~ion there is provided a composi~ion h~ving ~nti-surface weAr properties comprising a c~rrier and di4sol~ed ~nd/or disperse~ therein ~n effecti~e ~mount of ~ compound h~ving an~-surface wear properties char~cterised in that sa~d compound ~ a heteropol~r compound comprising at least one wholly unsaturated heterocyclic ~ix-membered rlng in which ~t least one unsub~tituted heteroatom ~oieey a~t8 fl~ ~ hydrogen acceptor ~nd in which s~id compound fllso compri~es ~t le~t one ~ydrogen donor moiety and in wh~ ch 6a~d heteropolAr ~ompound ~8 no substituent whlch by itself or together wie~ Rnother substituent or substltuents creAtes ~uch 6teric hindrance ~nd/or ~ender~ the molecule 80 ba~ic or ac~dic or 80 alters the steric geometry of ~he molecule ~ to prevent interaction of t~e hydrogen donor ~nd acceptor ~o~et~es of one molecule of the heteropol~r compound with the hydrogen ~onor ~nd ~cceptor moietie~ of ar.~t~er molecule of the heteropolar co~pound nor sny substituent which by it6elf or together with anotl~er subs~ituent or sub~tituent8 has the effec~ of solub~ ing said ~eteropol~r ~ompound in tbe ~elected c~rrier to the extent th~t migration of the ~eteropol~r co~pound eo the interfaces of ~he carrier with the CArr~ er environment ~ ~ prevented .
Tbe carrler m~y be a liq~i~ such fl8 ~ lubricating oil or ~ydrocarbon fuel for an internal combustlon eng~ne or flqueous 8ystem, or the carrier ~ay ~e a greAse or sem$-solid m~ter$al (non-Newtonian flu$d) such ~ bricat~ng greA~e or g~eAge-l~ke ~ubrican~. The cArrier m~y Also be a solid such as ~
pla8tic8 com~o~lte, e.g. a polyamide used ~n repa~ing 1 3372q2 or rebullding be~dlng surfaces. In the csse of liquid the content of heteropolar co~ound ~y be from 0.5%
to 4% by weigh~ b~ed on the totAl welghe of earrler and additi~e and ~n the c~se of grea6e~ or non-Newtoni~n fluld~ may be fro~ 3X to lOZ by weight ba~ed on ~e tot~l ~eight of e~rrier plufi ~dtiti~e.
Prefer~bly, in the cese of A liquid the contene of heteropol~r compound i~ gre~ter than lZ~ e.g. from l.lZ to 4% by weight ba~ed on the total weight of carrier and Addieive. The concentration ne~e~ry in ~ solid carrier will depend on ~he type of ~olid c~rrier lnvolved. In the ~a~e of polyamides 80~ewhat more ~dditl~e is ~ n general nece8s~ry th~n thAt required in a semi-soli~ for equivalent resul~s. This ~.~ the ca~e of ~ 'Poly~m~d' be~r~ng lO~ by welght based on the tOtfll wei~ht of 'Polyamidl' and additive was found satisf~ctory. However ~mounts of greater than 10~ e . g . 10 .1% to 20Z are preferred .
The preferred hydro~en ~cceptor moiety is one in~olvin~ nitrogen AS the heteroatom ~n the for~ of ~n -N~ moiety. The preferred hydrog¢n donor mo~ety l~ a hydroxyl group. Both 8UC~ mo~etie8 occur ~n the prefe~red heteropolAr compound of the in~ention which i~ 8-hydroxyquinoline:--~,~

The con~ensed ring sy~tem in the heteropolsr compounds u~eful in the invention m~y cone~1n up to four -N-moieties. ~ith prefer~bly up to two such moieties bein8 ~ncorpor~ted ~ ring form~ng a~o~s in ~ny one ~in~. Ot~er unsubs~ituted heteropol~ compound~
u~eful in the method And compos~tions of the pre~ent invention incl~de:

7,3 dihyd~oxypyridine ~u ~l H

4,6 ~ihydroxypyrimidine WQ~

2 pteridinol w4 2,4 quinolindiol ~
~~0~

2 , 3 d I hyd roxyq u 1 n ox a 1 I n ,i~
~æ~Lo ~

2.4 pterldinedlol ~ ~ ~
W~

6 p~rinol O
t~

~-0 3 phenanthridinol 2 phenanthrolinol 2 phenazinilol ~

A~ previously ind~cated the preferred heteropolar compound6 ~re uns~bstitued materl~l~. Substituents should not create steric hindr~nce w~ich prevents interaction of the hydrogen donor and ~cceptor moietie~. T~lus the provision of ~ ethyl group ortho to the -N- hyd~ogen ~cceptor mo~e~y of 8-hyd~oxy-quinoline to form the compo~nd:-~2-met~yl-8-hydroxy ~uninoline does not nl~terl~lly affec~ the ~etivity of this heteropolAr molecule in forming edsorption film on metal sur~ceo. The number a~d size of the ~ubstituent~ which can be toler~ted ~n ~he he~eropolar molecule depends on the number and posi~on of the hydrogen donor ~nd sceeptor moieties ln the molecule.
In gener~l t~e ~ubst~tuen~s groups should not exceed four atoms in number (e.g. in the case of hydro~arbyl the bu~yl group), preferably no ~ore th~n ~o fl~oms ~nd more preferably stlll only one e~rbon atom.
A good lndic~eion of whether ~terlc hindr~nee ~s 1 ikely to c~u~e problealfi i8 given by me~sur~ ng the ~dsorption-free energy of the compound in ~ue~tion.
If the s~orpeion-free energy fl~ me~sured on ~ copper surface is sub~t~nti~lly in the range of 3 to 6 Kc~l/mol then R teric hin~r~nce i8 unlikely ~o be problem .
Th~a invention will be further lllustraeed by reference to the following Examples w~l~ch ~re purely illu8tr~tive. In e~ch of the exa~ples the heteropol~r compound was 8 -hydroxyqulnol lne .
~LE 1 0 . 5% by we~ght of heteropol~r compound wa~
incorpor~ted in S~E 30 engine oll which we~ then u~ed in ~ ee6t-bed fully ~nstrumented W~irlepeel sy~eem.
The following re~ult~ were obtalned ~ ~hown ln Tables 1 to 5.

_17_ 1 337292 Table 1 C:OMPR~S~~

CYLIN~ 1 2 3 4 5 6 1 2 3 4 5 6 C~PRESSICN, lOSP~28 22 26 ~4 ~4 2230 30 28 26 26 26 Tablc 2 EU~ ~ONStk~I~ (af~er lOO km of r~mning) HEI~a~ AETER 15 ,000 km Rll~X:
COt~SUPTl~N UI~ lOOl~ AT ~ SPEED CF
4C)~h 5~ 60~h 701~m/h (a) 22.83 27.39 33.55 42.73 (b) 20.~6 ~5.97 31.25 39.84 (c) 20.32 23.47 28.4~ 35.5g T~le 3 WEA~ RAl~:S
WI~ HETE~LAR 0-0068 ~e/~
WIlH HE~OE~AR 0.003g Fe/ha~

T~ble 4 E~Cr~
t~.~ ~LAR 170.5 l~a ER~Cl~N MIDI~E E~E
162.5 kP~ ~' Table 5 EMISSION (Bo~ch Unit~
(~) Ground Revs (Tick-o~rer 6peed) (b) Full Throttle (Revs) 1 . 5 MAX PERMISSI~LE VALUE
WIlHO~JT HETE~OPOLAR WITH HETEROPOLAR
(a) (b) (-) (b) 0.9 1.7 0.6 1.2 The followin~ Ex~mples show the EP effect of adding t~le heteropol~r compound to different lubricant6.

EXAMPI.E 2 ~X'rRE?lE PRESSURE (EP) E~FECT
She l l Four Ba l l M~chine Lubr~c~ng ~'eàium; Lithium grea&e, with 3Z by welght of ~eteropolar co~pount.
WITIIOUT HETEROPOLAR welding at 27 - 2.27N
l~JITH llETEROPOLAR no welding at 37 E;XA~PL E 3 F~LEX LtJBRICANTS TESTER
To . L .P . Test 241t69 with O ~ 5X by weight of heteropol~r co~potJnd .
JAW L~D TIME TO FAILURE
S~E OIL WIT~lOUT ~IETEROP~LAR 3 ,OOON 3 m~ n lO 6ecs SAE OIL WITH l~:TE~OPOLAR 4,000N 5 min ~ote: JQW LOad 1000N increments for a period o~ one minute .

1 3372q2 CO~POS7 TE MATERIALS
'Polyamid' Be~ing w~ th lO~ of MoS2 co~posite additive, compared with a s~alilar bearing cont~ining 1070 of heteropolsr compound. The bearlng h~ving the heteropolar compound in the ' Polyamid ' lowered the fri~tiol~ by 30% ~18 compound ~o ehe bearing cont~ining t!le MoSz additive, NOISE REI~ TION
When t~e heeeropolar compou~d ~ incorpor~ted in t~e lubricant in ~ ba~k ~xle dlffeten~isl 8earing ~he noise redllced by ZdB. When the heteropol~r compound ~AS incorporAted in the lubricant in a Vauxhall As tr~
en~ ~ne ehe noise decreased by 8~dB to 80dB.

................................................ ~

Claims

1. A composition of matter for providing a lubricating regime in which adherent multimolecular layers of a heteropolar material are absorbed onto a surface to be protected from frictional wear, said composition of matter comprising:
a carrier for a heteropolar material; and an amount of a heteropolar material in said carrier effective to produce a multimolecular lubricating layer of the heteropolar material having anti-surface wear properties on a surface to be protected from frictional wear when said composition is brought into contact with such surface, said heteropolar material comprising a heteropolar compound having at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hinderance and/or renders the molecule so basic or acidic so as to alter a steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of the heteropolar compound nor any substituent or substituents has the effect of solubilizing said heteropolar compound in the selected carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented, said effective amount of said heteropolar material being heteropolar material in the composition which is available to migrate to the interfaces of the carrier with the carrier environment, and said effective amount being an amount of at least 0.5% by weight based on the total weight of carrier and heteropolar material.

2. A composition as claimed in claim 1, in which the heteropolar compound comprises up to three condensed unsaturated rings, one of which rings is said wholly unsaturated heterocyclic six-membered ring.

3. A composition as claimed in claim 2, in which one of said condensed rings is a five-membered unsaturated heterocyclic ring.

4. A composition as claimed in claim 2, in which all the condensed rings are six-membered unsaturated rings.

5. A composition as claimed in claim 1, in which the carrier is a liquid.

6. A composition as claimed in claim 5, in which the liquid is a lubricating oil.

7. A composition as claimed in claim 5, in which the liquid comprises at least one unsaturated hydrocarbon.

8. A composition as claimed in claim 5, wherein the heteropolar compound is present in the range of from 0.5 to 4% by weight based on the total weight of carrier and additive.

9. A composition as claimed in claim 5, in which the carrier is an aqueous liquid.

10. A composition as claimed in claim 5, in which the carrier is a liquid hydrocarbon fuel for an internal combustion engine.

11. A composition as claimed in claim 1, in which the carrier is a lubricating grease or grease-like material.

12. A composition as claimed in claim 11, wherein the heteropolar compound is present in the range 3% to 10% by weight based on the total weight of carrier and additive.

13. A composition of matter for providing a lubricating regime in which adherent multimolecular layers of a heteropolar material are absorbed onto a surface to be protected from frictional wear, said composition of matter comprising:
a solid plastic material carrier for a heteropolar material; and an amount of a heteropolar material in said carrier effective to produce a multimolecular lubricating layer of the heteropolar material having anti-surface wear properties on a surface to be protected from frictional wear when said composition is brought into contact with such surface, said heteropolar material comprising a heteropolar compound having at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hinderance and/or renders the molecule so basic or acidic so as to alter a steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of the heteropolar compound nor any substituent or substituents has the effect of solubilizing said heteropolar compound in the selected carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented.

14. A composition as claimed in claim 13, in which the solid plastics material is a polyamide.

15. A composition as claimed in claim 13, wherein the heteropolar compound is present in the range 10.1% to 20% base don the total weight of carrier and additive.

16. A composition as claimed in claim 1, in which the heterocyclic moiety which acts as a hydrogen acceptor is an -N=
moiety.

17. A composition as claimed in claim 16, in which the heteropolar compound contains up to four -N= moieties.

18. A composition as claimed in claim 1, in which the hydrogen donor moiety is an -OH group.

19. A composition as claimed in claim 1, in which the heteropolar compound is 8-hyadroxyquinoline.

20. A composition as claimed in claim 1, in which the heteropolar compound is selected from 2,3-dihydroxypyridine, 4,6-dihydroxypyrinidine, 2-pteridinol, 2-methyl 8-quinolinol, 2,4-quinolindiol, 2,3-dihydroxyquinoxalin, 2,4-pteridinediol, 6-purinol, 3-phenanthridinol, 2-phenanthrolinol and 2-phenazinol.

21. A lubricated article comprising:
a solid article having a surface to be protected from 2-body or adhesive wear; and a lubricating regime on said surface in which an adherent multimolecular lubricating layer of a heteropolar material having anti-surface wear properties is absorbed onto the surface, said heteropolar material comprising a heteropolar compound having at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hinderance and/or renders the molecule so basic or acidic so as to alter a steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of the heteropolar compound nor any substituent or substituents has the effect of solubilizing said heteropolar compound in a selected carrier therefor to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented, said heteropolar material being present in an effective amount, which effective amount is that amount which is available in the lubricated article for migration to the surface to be protected and is an amount of at least 0.5% by weight based on the total weight of carrier present and heteropolar material.

22. A method for reducing 2-body or adhesive wear on a surface which is subject to such wear by establishing on said surface a lubricating regime in which an adherent multimolecular layer of a heteropolar material having anti-surface wear properties is absorbed onto the surface, said method comprising the steps of:
adding said heteropolar compound to a carrier through which the heteropolar compound can migrate, said heteropolar compound being present in the carrier in an amount effective to produce said adherent layer on said surface when brought into contact therewith, said heteropolar material comprising a heteropolar compound having at least one unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hinderance and/or renders the molecule so basic or acidic so as to alter the steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of the heteropolar compound nor any substituent or substituents has the effect of solubilizing said heteropolar compound in said carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented, said effective amount of said heteropolar material being heteropolar material in the composition which is available to migrate to the interfaces of the carrier with the carrier environment, and said effective amount being an amount of at least 0.5% by weight based on the total weight of carrier and heteropolar material; and bringing said carrier and said heteropolar compound into contact with at least a portion of said surface for a time sufficient to allow said compound to migrate onto the surface and form said layer.

23. A method as set forth in claim 22, wherein said bringing step includes causing said composition to contact said surface continuously.

24 A method as set forth in claim 22, wherein said bringing step includes causing said composition to contact said surface intermittently.

25. A method of reducing 2-body or adhesive wear on contacting surface which in relative motion are subject to adhesive wear by applying a multimolecular lubricating layer onto at least one of said contacting surfaces.

26. A method as claimed in claim 25 in which the multimolecular lubricating layer is formed in situ on at least one of said contacting surfaces by applying a lubricating compound to said contacting surface via a carrier.

27. A method as claimed in claim 26 in which the lubricating compound is a heteropolar compound.

28. A method as claimed in claim 26 in which the lubricating compound is a heteropolar compound comprising at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and said compound further comprises at least one hydrogen donor moiety.

29. A composition as claimed in claim 1, wherein said layer has a thickness in the range of from 1x10-9m to 1x10-6m.

30. A article as claimed in claim 21, wherein said layer has a thickness in the range of from 1x10-9m to 1x10-6m.

31. A method as claimed in claim 22, wherein said layer has a thickness in the range of from 1x10-9m to 1x10-6m.

32. A method for lubrication of contacting surfaces which are subject to 2-body or adhesive wear comprising applying between said surfaces a lubricating quantity of a heteropolar compound having at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hinderance and/or renders the molecule so basic or acidic so as to alter a steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of the heteropolar compound nor any substituent or substituents has the effect of solubilizing said heteropolar compound in the selected carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented.

33. A lubricated article comprising a surface to be protected against 2-body or adhesive wear and a lubricating regime at said surface providing an adherent layer of a heteropolar material for protecting said surface against such wear.

34. A lubricated article as claimed in claim 33, in which said lubricating layer has a thickness of 1x10-9m to about 1x10-6m.

35. A method of reducing 2-body or adhesive wear on a surface which is subject to such wear by establishing on said surface a lubricating regime in which an adherent multimolecular lubricating layer of a heteropolar material is absorbed onto the surface, said method comprising the steps of:

adding said heteropolar compound to a carrier through which the heteropolar compound can migrate, and bringing said carrier and heteropolar compound into contact with a portion of said surface to be treated for a time sufficient to allow said heteropolar compound to migrate onto said surface and form a protective multimolecular lubricating layer thereon.

36. A method of reducing wear on a surface which is subject to frictional forces which comprises forming and maintaining on said surface a protective layer characterised in that said protective layer is a multi-molecular layer of a heteropolar compound comprising at least one wholly unsaturated heterocyclic six-membered ring in which at least one unsubstituted heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety, and in which said heteropolar compound has no substituent which by itself or together with another substituent or substituents creates such steric hindrance and/or renders the molecule so basic or acidic or so alters the steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of the heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of said heteropolar compound nor any substituent which by itself or together with another substituent or substituents has the effect of solubilizing said heteropolar compound in a selected carrier to the extent that migration of the heteropolar compound to the interfaces of the carrier with the carrier environment is prevented and in which the protective layer is formed on the surface to be protected by contacting at least a portion of the said surface with a composition comprising a carrier and dissolved and/or dispersed therein an effective amount of said heteropolar compound.

37. A method as claimed in claim 36, in which at least a portion of the surface to be protected is continuously contacted with said composition.

38. A method as claimed in claim 36, in which at least a portion of the surface to be protected in intermittently contacted with said composition.

39. A method as claimed in any one of claims 36 to 38, characterised in that the heteropolar compound comprises up to three condensed unsaturated rings, one of which rings is said wholly unsaturated heterocyclic six-membered ring.

40. A method as claimed in claim 39, characterised in that one of said condensed rings is a five-membered unsaturated heterocyclic ring.

41. A method as claimed in claim 39, characterised in that all the condensed rings are six-membered unsaturated rings.

42. A method as claimed in any one of claims 36 to 38, in which the carrier is a liquid.

43. A method as claimed in claim 42, characterised in that the liquid is a lubricating oil.

44. A method as claimed in claim 43, characterised in that the lubricating oil comprises at least one unsaturated hydrocarbon.

45. A method as claimed in claim 44, characterised in that the heteropolar compound is present in the range 1.1% to 4% by weight based on the total weight of carrier and additive.

46. A method as claimed in claim 42, characterised in that the carrier is an aqueous liquid.

47. A method as claimed in claim 42, characterised in that the carrier is a liquid hydrocarbon fuel for an internal combustion engine.

48. A method as claimed in any one of claims 36 to 38, characterised in that the carrier is a lubricating grease or grease-like material.

49. A method as claimed in claim 48, characterised in that the heteropolar compound is present in the range 3% to 10% by weight based on the total weight of carrier and additive.

50. A method as claimed in any one of claims 36 to 38, characterised in that the carrier is a solid plastics material.

51. A method as claimed in claim 50, characterised in that the solid plastics material is a polyamide.

52. A method as claimed in claim 51, characterised in that the heteropolar compound is present in the range 10.1% to 20% based on the total weight of carrier and additive.

53. A method as claimed in any one of claims 36 to 38, 40, 41, 43, 44 to 47, 49, 51 and 52 characterised in that the heterocyclic moiety which acts as a hydrogen acceptor is an -N= moiety.

54. A method as claimed in claim 53, characterised in that the heteropolar compound contains up to four -N= moieties.

55. A method as claimed in any one of claims 36 to 38, 40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the hydrogen donor moiety is an -OH group.

56. A method as claimed in any one of claims 36 to 38, 40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the heteropolar compound is 8-hydroxyquinoline.

57. A method as claimed in any one of claims 36 to 38, 40, 41, 43, 44 to 47, 49, 51, 52 and 54, characterised in that the heteropolar compound is selected from 2,3-dihydroxypyridine, 4,6-dihydroxypyrinidine, 2-pteridinol, 2-methyl 8-quinolinol, 2,4-quinolindiol, 2,3-dihydroxyquinoxalin, 2,4-pteridinediol, 6-purinol, 3-phenanthridinol, 2-phenanthrolinol and 2-phenazinol.